Hi,
I don't know if this is helpful but I'm currently using staff in production environments for an application written in C++ that communicates with a webserver and handles around 100K subscribers...
The framework has some limitations, mainly because of the limitations of Axis2/C, but it worked for my application. (they're all listed in
http://code.google.com/p/staff/wiki/KnownBugsAxis2c)
I've tried also Wso2 for c++ , and I had the same limitations that came from Axis2/C, plus some memory leaks, and I asked some questions on their forum and never got a reply... I've liked more Staff because whenever I had an issue I could report it and got an answer, and the issues got solved quickly. Also the interface is easy to use, and it's a lot easier to use than Axis2/C alone... (Of course all of this is just my opinion, based on my experience. I don't mean to discredit in any way Wso2 in any way)